I am working on a world situated on the Earth.
There is normal gravity, normal conditions of living - normal everything, except the human population itself.
Humanity as a species evolved to its peak, and now everybody has slight elemental powers based on fire, earth, water and air.
Nothing is overpowered. If you have no source, you cannot do voodoo elemental stuff. If you have a source, you can manipulate with it to the max range about 10 meters. I can not create a resource of my manipulation neither can turn in it. I can sense the water, I can do waves, for example, or water walls.
Here is a problem. I am a water "elementalist". Can I walk on water in the Earth environment?